Monochorionic twins

Various types of chorionicity and amniosity (how the baby's sac looks) in monozygotic (identical) twins as a result of when the fertilized egg divides.

Monochorionic twins are monozygotic (identical) twins that share the same placenta. If the placenta is shared by more than two twins (see multiple birth), these are monochorionic multiples. Monochorionic twins occur in 0.3% of all pregnancies.[1] Seventy-five percent of monozygotic twin pregnancies are monochorionic; the remaining 25% are dichorionic diamniotic.[2] If the placenta divides, this takes place before the third day after fertilization.[2]

  1. ^ Cordero L, Franco A, Joy SD, O'shaughnessy RW (December 2005). "Monochorionic diamniotic infants without twin-to-twin transfusion syndrome". J Perinatol. 25 (12): 753–8. doi:10.1038/sj.jp.7211405. PMID 16281049.
  2. ^ a b Shulman, Lee S.; Vugt, John M. G. van (2006). Prenatal medicine. Washington, D.C.: Taylor & Francis. p. 447. ISBN 0-8247-2844-0.